Dual monitors, off-screen space

I have an external monitor (1920x1080) that has a higher resolution than my laptop screen (1366x768). I have the laptop screen set as the primary output, and the external screen set to the right, with the tops of the screen aligned. At the bottom of the smaller screen, there is an area where the cursor can travel off-screen. Windows can even be place in this space and be lost to view.

Is there a way to fix this? My card is an “Arrandale Integrated Graphics Controller,” if that helps. Here’s a screen shot of my settings; I’ve highlighted the area in question in red:

http://img404.imageshack.us/img404/1199/settingsa.png

Thanks!

I should add that I’m using openSUSE 12.1 and KDE.

KDE and Gnome DE’s both use the RandR (Resize and Rotate) extensions to manage dual screens as one big desktop space (with virtual size 3286 x 1080 in your case). The behaviour you see is normal for two displays with differing display resolutions. When I’m at my office at work, I sometimes connect my laptop (1680x1050) to an external monitor (1368x768), and I have the bottom of the KDE desktop cropped (missing from view) on my external monitor (as expected). In your case, with the laptop display having the lesser resolution, it could result in the task bar being out of view (assuming its at the bottom). I guess that would be a problem. You may have to be a bit more explicit in how you’d like to have the desktop areas displayed on your laptop when the external monitor is active, then someone can probably advise further.

Well, windows maximize properly, and the task bar anchors to the bottom of the visible screen. I guess I’m really just trying to figure out how to keep the mouse/cursor from traveling off-screen.

XRandR is a new one for me…(searching)…

If I were to change my panning settings per this, is there a way to reliably back-up and restore my current settings before proceeding?

And would the necessary command be:
xrandr --output VGA1 --mode 1366x768 -fb 1366x768 --panning 1366x768

If I were to change my panning settings per this, is there a way to reliably back-up and restore my current settings before proceeding?

Any configuration you make with the xrandr command will only persist as long as the current X-session. Restarting the X-server with CTRL-ALT-Backspace (twice) will restore to default. You can add any desired xrandr command (within an executable script) to your startup directory.

And would the necessary command be:
xrandr --output VGA1 --mode 1366x768 -fb 1366x768 --panning 1366x768

I’m not clear about what you’re trying to achieve with that command and with respect to dual screen operation. It essentially allows you to set the virtual screen size, then display only a portion of it, but you can pan across the virtual desktop with your mouse. For example

xrandr --output LVDS1 --mode 1366x768 --panning 2000x1000

Hmmm… after digging some more… I thought --panning was a per output option?

xrandr
–fb 3286x1080
–output LVDS1 --mode 1366x768 --pos 0x0 –panning 1366x768
–output VGA1 --mode 1920x1080 --right-of LVDS1

…the above command sets my screen layout how I want it, except when I add the part in red, it just doesn’t work (doesn’t make any changes). If I restrict the panning in LVDS1 to the screen size of LVDS1, shouldn’t it keep the cursor from going “off-screen?”

The following command brings the “empty space” onto the visible area of LVDS1, but of course the display is smooshed (vertically).

xrandr --output LVDS1 --scale 1x1.40625

…the above command sets my screen layout how I want it, except when I add the part in red, it just doesn’t work (doesn’t make any changes). If I restrict the panning in LVDS1 to the screen size of LVDS1, shouldn’t it keep the cursor from going “off-screen?”

No, that will just define the panning area (window size). The xrandr man page mentions

--panning widthxheight+x+y[/track_widthxtrack_height+track_x+track_y[/border_left/border_top/border_right/border_bottom]]]
    This option sets the panning parameters. As soon as panning is enabled, the CRTC position can change with every pointer move. The first four parameters specify the total panning area, the next four the pointer tracking area (which defaults to the same area). The last four parameters specify the border and default to 0. A width or height set to zero disables panning on the according axis. You typically have to set the screen size with --fb simultaneously. 

As an experiment I cofigured my dual desktop environment like this

xrandr --output VGA1 --auto --right-of LVDS1 --mode 1366x768 --panning 1366x1050+1680+0

so that the VGA1 display matched the vertical size of my laptop display (1680x1050). I could then keep the mouse cursor in view, but of course the desktop window of the external monitor moves when I hit the top or bottom of the desktop image with my mouse cursor. I don’t like panning, and prefer the default KDE dual screen behaviour.

Hmmm… If I have to pick between panning and the mouse going “off-screen,” I suppose I’ll just deal with things as-is. It’s strange though, this doesn’t seem to be an issue in Ubuntu (gnome?).

I don’t see it as an issue, it’s a desktop feature/design. I noticed (after trying) that my Windows XP dual screen behaviour is as you’ve described (the mouse is constrained to the desktop), and maybe the Gnome DE does the same.

Maybe you should consider submitting an openFATE request…

openSUSE: Openfate documentation - openSUSE

Or take it upstream…

https://bugs.kde.org/

https://forum.kde.org/

I have the exact same problem, except that the invisible space between laptop and monitor is on side edge shared between the displays. Did you find a solution?

And you also have openSUSE 12.1 and KDE installed?

I am running Tumbleweed with KDE 5.5. See my post here, with a workaround:

https://www.reddit.com/r/linuxquestions/comments/4c2o4p/what_does_panning_and_fb_in_xrandr_stand_for/

Plasma 5 has Problems with 2 Monitors.

Till now I haven’t faced problems with plasma 5 on dual monitor setup. Right now the problem I face is with monitors with different DPI which is problem with Linux and X.org in general.

Please don’t reuse a > 3 year old thread that’s about some ancient openSUSE version.

So I had some troubleshooting and I have created a recent post: https://forums.opensuse.org/showthread.php/516792-Empty-space-between-monitors